SAN FRANCISCO – During the week, Roberto Heckscher was a socially awkward accountant who drove a Saturn and kept an office above a flower shop in a quiet neighborhood. On the weekends, he transformed into a high-rolling casino “whale” who enjoyed VIP treatment worthy of a sheik.

He managed to keep this double life secret from most – especially the hundreds of mostly elderly and working class who invested their life savings with him – until the night of June 8, 2009. That’s when he swallowed 90 sleeping pills and lay down to die.

One of the longest-running Ponzi schemes in U.S. history had finally collapsed.

Heckscher survived his suicide attempt and is in county jail waiting assignment to a federal prison. U.S. District Court Judge Susan Illston sentenced him to 20 years in prison for duping at least 290 investors out of at least $50 million over 30 years.

Heckscher’s scam is notable for the patient, methodical way in which he squeezed so much money from investors of mostly modest means.

Many of the victims were clients of Henry Irving, a well- respected neighborhood tax guy in the city’s foggy Sunset District, who hired then-17- year-old Heckscher in 1973. Five years later, Irving was on his deathbed and sold the business to Heckscher. Many of Irving’s clients stayed with Heckscher at the encouragement of Irving’s son, Daniel, who lost $1.7 million in the scheme, according to court documents.

Heckscher used the respected accounting business to insinuate himself into a tightknit neighborhood of modest homes and crowded Catholic churches, even though he was born in South America to Jewish parents who fled Nazi Germany.

No one suspected that Heckscher was interested in anything more than his clients’ well-being as he consistently pressed them for increased investments.

Heckscher “concocted an elaborate scam … in large part to fuel a secret, second, sordid life of gambling in the casinos of Las Vegas, Lake Tahoe and Atlantic City,” Assistant U.S. Attorney Timothy Lucey wrote in court papers arguing for a lengthy prison sentence.

Many of his investors are now losing homes, businesses and putting off medical treatment and are cursing themselves for trusting Heckscher like a family member.

The judge appointed an investigator to dig into Hecksher’s holdings. The judge scheduled a July 29 hearing to discuss victim restitution.